1. Field of the Invention
The present invention relates to a nitride semiconductor laminated structure and an optical semiconductor device, and methods for producing the same, in particular, a nitride semiconductor laminated structure having a p-type nitride semiconductor layer satisfactory in crystallinity and sufficiently low in electric resistivity, an optical semiconductor device, and methods for producing the same.
2. Background Art
In these years, for the purpose of high densification of optical disks, research and development of semiconductor lasers capable of emitting light from the blue region to the ultraviolet region are being actively conducted. Such blue-violet laser diodes (hereinafter, laser diode is abbreviated as LD) each have a nitride semiconductor laminated structure made of a nitride such as GaN, GaPN, GaNAs, InGaN, AlGaN or AlGaInN. Optical semiconductor devices having an AlGaInN-based laminated structure have already been put into practical use.
As a method for producing a nitride semiconductor laminated structure, there has been proposed a method in which a p-type GaN layer is formed by using only ammonia as a Group V material, and thereafter a p-type GaN layer is formed by using only trimethylhydrazine as a group V material (see, for example, Japanese Patent Laid-Open No. 2003-178987).